Multiple stage colloid mill with apertured rotor-top feed means



June 5, 1956 w. RIETH 2,749,053

MULTIPLE STAGE COLLOID MILL WITH APERTURED ROTOR-TOP FEED MEANS Filed April 15 1953 2 Sheets-Sheet l 5 i; /Z INVENTOR A /2Q & WALTER R/ETH BY I ATTORNEY June 5. 1956 w. RIETH 2,749,053

MULTIPLE STAGE COLLOID MILL WITH APERTURED ROTOR-TOP FEED MEANS Filed April 15, 1953 2 Sheets-Sheet 2 'Illllll x I "'1',

/6 X 4P1 E INVENTOR WALTER R/E TH I c' 5 BY ATTORNEY MULTIPLE STAGE COLLUID MILL WITH APER- TURED RGTOR-TOP FEED MEANS Walter Rieth, Braunlage (Harz), Germany, assignor, by mesne assignments, to Probst & Class, Rastatt, Baden, Germany, a corporation of Germany This invention relates to a colloid mill.

One object of this invention is a new colloid mill having a more effective comminuting elfect than prior known mills of this type, and which will even comminute substances which were immune to extensive dispersion in the prior known mills. This, and still further objects, will become apparent from the following description, read in conjunction with the drawings, in which Fig. 1 shows a perspective view of a colloid mill in accordance with the invention with the housing partially cut away,

Fig. 2 shows a longitudinal section through a tooth of the part of Fig. 1,

Fig. 3 shows a cross-section of the opposed toothing on the parts 4 and 5 in Fig. 1,

Fig. 4 shows a detailed cross-sectional view of a portion of the toothing 14a of the embodiment shown in Fig. 1;

Fig. 5 shows a detailed cross-sectional view of a portion of the toothing 12a of the embodiment shown in Fig. 1;

Fig. 6 shows a detailed cross sectional view of portions of the toothing 13a of the embodiment shown in Fig. 1;

Fig. 7 shows a side elevation partially in longitudinal section of the embodiment of the mill shown in Fig. 1;

Fig. 8 shows a longitudinal section of the rotor of the mill shown in Fig. 1, and I Fig. 9 shows a cross-section of the rotor shown in Fig. 8 through the window portion.

The mill in accordance with the invention has a stationary housing in which a vertical rotor is rotatably mounted. The outer surface of the rotor and the inner surface of the housing, respectively, define lands and grooves which form the comminuting teeth of the mill. The rotor is in the form of a hollow cylinder having a closed bottom and open top. A feed funnel or hopper 1 leads into an opening at the top of the mill housing, so positioned that material passed through the hopper and opening will fall into the hollow interior of the rotor. The rotor is thus formed as a receiver container and the material to be groundis introduced axially through the feed hopper i and the opening in the mill housing.

Apertures or windows 19 are defined through the rotor from the interior thereof through to the space between the exterior and the inner wall of the housing. In the embodiment shown in the drawing four such windows 19 are provided through the upper portion of the rotor.

As mentioned, the inner wall of the housing and the outer surface of the rotor have lands and grooves which define the grinding or comminuting teeth of the mill. The teeth as shown rnn obliquely and the toothing of the housing corresponds to that of the rotor, except that it slants in the opposite direction. Material in the space between the inner wall of the housing and the rotor will thus be comminuted as the rotor rotates and the space defined between these two elements is a comminuting nited States-Patent O "tions per minute.

2,749,053 Patented June 5, 1956 space or gap. The rotor and the housing are so dimensioned and positioned that this gap decreases in a downward direction.

In accordance with the invention, the inner wall of the housing which defines the comminuting toothing is subdivided into two portions 3 and 4 and the oblique toothing, having a direction opposite to the toothing of the rotor, changes from coarser to finer teeth.

The rotor is subdivided into two portions 2 and 5. The bridging surfaces between the windows 19 on the upper portion of the rotor 2 have coarse toothing 14 and the toothing 14a on the portion 3 of the housing corresponds to this toothing, except its oblique direction is opposite. The action of these two portions on material in the gap therebetween as the rotor rotates will effect a cutting of the material and shearing as a scissors and thus effect a pre-comminution of the material.

The second portion of the rotor 5 is further sub divided with respect to the toothing defined thereon into an upper and lower portion. The upper portion has somewhat finer toothing 12 and the portion of the housing 4 opposed thereto has corresponding opposed toothing 12a. The lower part of the second portion of the rotor has still finer toothing 13 and the lower portion of 4 of the housing opposed thereto has corresponding opposed fine toothing 13a.

In Fig. 2, which is a longitudinal section of a portion of the rotor part 5 along one of the teeth, it can be seen how the coarser toothing 12 changes over to the finer toothing 13 in the lower portion.

In Fig. 3, which shows in detail a cross-sectional view of opposed portions of 4 and 5, it can be seen how opposed toothing i2 and 12a correspond but the slant in opposed oblique directions to effect the shearing action.

In Fig. 7, the toothing 14, 12 and 13 of the rotor can clearly be seen and in Figs. 4, 5 and 6 the cross-sectional view clearly shows the shape of the toothing of the portions 3 and 4 of the housing. Toothing 14 of the rotor corresponds exactly to the toothing 14a except for the slanting in the opposite oblique direction. The same is true of the toothing l2 and 12a, 13 and 13a.

The lower portion of the rotor is developed as a discharge plate or tray 6 and the space about this discharge plate is in communication with the discharge tunnel or spout 7.

The rotor is rotated in the housing by means of a motor positioned in the casing 10 which is connected to the rotor in any conventional manner and which in itself may be of any conventional or known design. The motor, for example, may rotate the rotor at about 300 revolu- The motor may be, for example, a vertical motor positioned in the casing 10 and connected by a vertical shaft to the rotor.

The motor positioned in the casing 10 rotates the shaft 11 which extends through the portion of the housing 17 and can best be seen in Fig. 7. The shaft 11 is connected to the rotor by means of a key as is shown in Fig. 8. A plate le is provided around the shaft 11 for moisture protection.

The'gap between the inner wall of the housing and the rotor may be regulated by the ring 8 and handles 9 as is best seen in Figs. 1 and 7. The rotor and the inner wall of the housing define opposed frusto-conical surfaces and the ring 8 is threaded to the lower portion of the housing. The two portions of the housing are firmly screwed together, as seen in Fig. 7. These portions cannot rotate with respect to the remainder of the housing, due to a key arrangement, but may move vertically with respect to the rest of the housing. The cover of the housing is screwed into the housing portion 3 and presses against the top of the ring 8 in sliding contact therewith,

so that when the ring 8 is screwed up, it slides in contact with this cover, forcing the cover and the connected portions 3 and 4 up with it. When the ring 8 is screwed down it presses against a shoulderon the portion 3, forcing it down with it. By turning the handles, the ring may thus be screwed upwardor down, thus moving the portions 3 and 4 up anddown, and thus varying the gap between the inner wall of the housing and therotor.

The construction of the rotor, the windows 19 and the connection of the rotor to the shaft 11, can best be seen from Figs. 8 and.9. In the cross-section as shown in Fig. 9 through the portion of the rotor in the area of the windows, the shape of a bridge member 18 betw een the windows can clearly be seen. The coarse toothing 14 as shown in Fig. 1' is defined on these bridge members 18. i v

In operation, the rotor is caused to rotate by means of the motor. The material to be comminuted is fed into the feed hopper 1 and dropsaxially into the hollow interior of the rotor. Due to the centrifugal force, the material is thrown to the walls of the rotor and passes through the windows 19 into the comminuting gap formed between the rotor and the inner wall of the housing. The material is then subjected to a shearing action by the toothing 14 of the bridge members between the windows of the upper portion 2 of the rotor and the opposed toothing 14 of the upper portion 3 of the inner housing wall. This will effect a pre-commiuution of the material. The material will then be forced downwardly through the narrowing gap and be subjected to the action of the toothing of the lower portions of the rotor and inner housing wall, so that a finer comminution will take place and a frictional comminution will take place to a large extent in connection with the fine toothing. The material will then, after beingcomminuted, drop onto the discharge plate 6 and be thrown from this plate by centrifugal force out of the discharge spout 7. As mentioned, the fineness and degree of comminution and the adjustments may be made by merely rotating the handles 9.

The portions of the ,mill which come in contact with the material to be ground should, of course, be resistant to corrosion and abrasion,.and therefore should advisedly be constructed of a high quality alloy steel. The same and possibly hard metals should be used for the cutting edges, i. e., the teeth. These high-quality, structural ma: terials need, however, only be used for the parts which come into contact with the material to be ground.

By having the toothing of the housing and the rotor oblique in opposite direction and changing from a coarse typeof toothing to a finer type of toothing in accordance with the invention, a cutting action similar to that of scissors is assured in operationin addition to the grinding action. This makes it possible to comminute even substances which, in previously known devices, had proven immune to extensive dispersion of this type.

I claim:

1. Colloid mill comprising a mill housing, a hollow rotor mounted within said housing for rotation about a substantially vertical axis, said rotor being substantially open at the top and closed at the lower portion, amaterial inlet defined at the upper portion of said housing positioned for the passage of material into the hollow interior of said rotor, aperture windows defined through Ifl said rotor for the passage of material from the interior to the exterior thereof by centrifugal force upon rotation of the rotor, oblique toothing defined on the exterior of said rotor, opposed oblique toothing defined on the inner wall of said housing spaced from the toothing of said rotor to define a comminution gap therebetween, said toothing being subdividedhorizontally into at least two portions with coarse toothing defined on the upper portion changing to finer toothing on the lower portion, a material discharge defined at the lower portion of said housing and means for rotating said rotor.

2. Colloid mill according to claim 1, in which said rotor is horizontally subdivided into at least two portions, said portions having toothing corresponding to the opposed toothing on the inner wall of said housing.

3. Colloid mill according to claim 2, in which said aperture windows are defined through the upper portion of said rotor and in which the bridge members connecting said windows define coarse toothing.

4. Colloid mill according to claim 3 in which said rotor is horizontally subdivided into at least three portions changingover on each portion in a downward direction to finer toothing, and in which the inner wall of said housing defines opposed corresponding toothing.

5. Colloid mill according to claim 4 in which the outer surface of said rotor defines a downwardly widening frusto-conical shape and in which the opposed inner surface of said housing defines an opposed frusto-conical shape.

6. Colloid mill according to claim 1, in which said rotor defines a downwardly widening frusto-conical shape and in which the opposed inner wall of said housing defines an opposed frusto-conical shape.

7. Colloid mill according to claim 6 in which the comminution gap defined between said rotor and inner housing wall narrows in a downward direction.

8. Colloid mill according to claim 7 including means for varying the vertical position of the opposed inner housing wall to said rotor to thereby vary said comminution gap.

9. Colloid mill according to claim 8 in which said material discharge comprises a tray defined at the lower portion of s aid rotor and a discharge spout defined at the lower portion of said housing adjacent said tray, whereby, upon rotation of said rotor, the centrifugal force will throw material off said tray out through said spout.

10. Colloid mill according to claim 9 in which said .rotor is horizontally subdivided into at least three portions, changing over on each portion in a downward direction to finer toothing.

References Cited in the file of this patent UNITED STATES PATENTS 

